This invention relates generally to lighter-than-air balloons and more particularly to tether systems for balloon rides.
Tethered balloon amusement rides have become a popular alternative to traditional, free-flying hot-air balloon rides. A tethered balloon system typically includes a balloon, a passenger-carrying gondola (also referred to as a “basket”), and one or more tethers (e.g., cables, ropes, lines or the like) that hold the balloon in a confined area, limit the extent of rise of the balloon and prevent the balloon from achieving free flight. While free-flying hot-air balloon rides are available to the public in many localities, the cost for such rides is generally quite high. A tethered balloon amusement ride provides the opportunity to experience ballooning in or near central metropolitan areas and at a lower per passenger cost.
One common balloon tethering system is a multi-point system using a number of tethers, typically three or more. In this case, each tether has one end secured to the ground and the other end attached to a point on the balloon, such as the top of the gondola. The tethers are spaced around the balloon so as to restrain movement in all directions horizontally and limit the balloon's rise. Such multi-point tethering systems are effective but require an excessive amount of ground area and tend to be difficult to operate.
Single tether systems are also known. A current design utilizes a spherical balloon envelope and an annular or donut-shaped gondola having a large opening or hole in the center. The large opening allows a single tether to pass through the center of the gondola and attach directly to the envelope via a load-bearing ring. The result is that the gondola structure itself does not bear the burden of the working loads; the working loads bypass the gondola and are handled by components better suited to handling such loads. These systems are designed to carry large numbers of people, such as up to 30 passengers at a time. In one design, the diameter of the central opening in the gondola is 13 feet, and the balloon envelope is 72 feet in diameter. Large volumes of passengers are needed to cover the considerable manufacturing, startup, and operating expenses for such systems.
When operating in calm winds, the envelope and gondola rest directly above the ground connection point, held securely by the tether. The tether is oriented vertically, centered in the central opening of the gondola. When the wind blows, the envelope and gondola are displaced in the direction of the wind and are no longer directly over the ground connection point of the tether. This displacement will cause the tether to be deflected or slanted off vertical. In response to the deflection of the tether, the load ring to which the tether is attached will tilt. Because the gondola is also suspended from this load ring via its own cables, the gondola will tilt as well, potentially unnerving the passengers. If the balloon is displaced to the extent that the tether is deflected approximately 30 degrees from vertical, the tether comes into contact with the inside of the gondola center opening, which can cause extreme and unsafe tilting of the gondola.
Accordingly, there is a need for a balloon amusement ride tether system that enables use of a smaller, lighter, less costly gondola and that better minimizes gondola tilt.